deprecation warning

[sserkez]

curretlny the code works with pyqtgraph v 0.10.0

if upgraded to 0.11.0, the exception will arise:

File "/home/andrei/Documents/pyhirex/hirex.py", line 291, in init
    self.analysistool = AnalysisInterface(parent=self)
  File "/home/andrei/Documents/pyhirex/analysis_spec.py", line 57, in init
    self.add_hist_full_widget()
  File "/home/andrei/Documents/pyhirex/analysis_spec.py", line 370, in add_hist_full_widget
    self.histogram_full_curve = self.histogram_full.plot(stepMode=True,  fillLevel=0,  brush=(100,100,100,100))
  File "/home/andrei/anaconda3/lib/python3.8/site-packages/pyqtgraph/graphicsItems/PlotItem/PlotItem.py", line 640, in plot
    item = PlotDataItem(*args, **kargs)
  File "/home/andrei/anaconda3/lib/python3.8/site-packages/pyqtgraph/graphicsItems/PlotDataItem.py", line 185, in init
    self.setData(*args, **kargs)
  File "/home/andrei/anaconda3/lib/python3.8/site-packages/pyqtgraph/graphicsItems/PlotDataItem.py", line 453, in setData
    self.updateItems()
  File "/home/andrei/anaconda3/lib/python3.8/site-packages/pyqtgraph/graphicsItems/PlotDataItem.py", line 497, in updateItems
    self.curve.setData(x=x, y=y, **curveArgs)
  File "/home/andrei/anaconda3/lib/python3.8/site-packages/pyqtgraph/graphicsItems/PlotCurveItem.py", line 335, in setData
    self.updateData(*args, **kargs)
  File "/home/andrei/anaconda3/lib/python3.8/site-packages/pyqtgraph/graphicsItems/PlotCurveItem.py", line 382, in updateData
    raise Exception("len(X) must be len(Y)+1 since stepMode=True (got %s and %s)" % (self.xData.shape, self.yData.shape))
Exception: len(X) must be len(Y)+1 since stepMode=True (got (0,) and (0,))